The present invention is a cooking device and, more particularly, a cooking device that uses steam for cooking. When compared to other forms of cooking, direct steam cooking, where the steam cooks by directly contacting the food, provides certain advantages including (1) reduced physical break-up of the food because the food is not generally disturbed during cooking, (2) reduced preparation time because of reduced handling and faster cooking time, (3) relatively constant temperature, even cooking, and (4) better retention of water soluble vitamins such as B and C.
The recognition of the benefits of steam cooking is not new. In fact, the ancient Chinese are known to have held bamboo containers over pots of boiling water in order to steam vegetables and fish. In the seventeenth century, the steam pressure cooker was developed in France and has since enjoyed renewed popularity in the past decade. Indeed, cooking with steam using the venerable double boiler (a metal strainer fitting on top of a pot of boiling water) remains a popular way to prepare meats, fish, and vegetables.
In modern times, people also tended to eat in restaurants more often. Busy schedules and a greater number of dual income households have increased interest in rapidly prepared food that is both healthy and inexpensive. In some cases, cooking with steam may offer an excellent way to achieve both objectives.
Unfortunately, direct cooking with steam remains time-consuming and cumbersome for quick-service convenience restaurants and many traditional restaurants. Little technological progress has been made in direct steam cooking beyond the double-boiler approach, where the user boils a pot of water, and then starts the cooking process by setting the food in a strainer atop the pot. The user stops the cooking process by physically removing the food from the steam source. While simple in terms of equipment needed, this process is inefficient because the user must maintain a pot of boiling or near-boiling water for the occasional order, and must carefully monitor the steaming food in order to prevent overcooking, which is easy to do with direct steam cooking. Also, the double boiler presents a potential safety hazard because of the possibility of direct contact with the boiling water and steam. In a hectic restaurant kitchen, such a control problem prevents direct contact steam cooking from being used for anything but expensive, specialty dishes.
In contrast, indirect steam cookers have been refined and are quite common in the restaurant environment. A typical indirect steam cooker is shown by the White ('706) reference that has multiple, manually controlled steam circuits that warm various pots on a table. The system heats food indirectly in that the steam heats pots containing food rather that by direct contact between the steam and the food. While the White reference dates from 1927, modern equipment based on this idea is available in various forms such as buffet warmers, chaffing dishes and steam jacket kettle cookers. The idea can be seen in both individual cookers and in plural systems with more than one pot. Steam jacket cookers come in a wide range of sizes adapted to different types of food. While the indirect cooking method is efficient for some applications, it does not provide the same health benefits of direct steam cooking.
Other inventors have responded to these problems by finding better ways to cook food by direct contact with steam. For example, Bourgeois ('852 & '321) is typical of this development in which a gas burner is used to heat a pot that is partially filled with water to generate steam. Inside the pot sits a removable wire rack on which the user can place food items to be steamed. The cooked food is then withdrawn from the pot by removing the rack. The cooking is self-contained and rapid but the drawbacks are (1) larger-sized cooking equipment because of the presence of boiling water in the same vessel where the food is steamed, (2) food must be transferred from a rack to another serving dish because the wire rack is not suitable for customer service, and (3) the system contains the same limitations as a double-boiler, since the user controls the cooking of the food by manually removing the rack and the food from the cooker when it is done.
Although equipment is commonly available for commercial seafood processors (e.g. canneries) to cook seafood at high, steady production rates using direct contact steam, such equipment is not suited to resolve the problems of cooking with direct steam in a restaurant environment. The high production rate systems use conveyor belts to move the food past steam jets to achieve even cooking, and therefore must receive a continuous supply of raw food. Consequently, they do not allow for convenient segregation of food into individual serving portions, and require a large amount of energy even when a small volume of food is to be cooked. These systems are often complex and require a large amount of floor space not commonly found in small restaurants and taverns.
Therefore the need exists for a direct steaming system that enables a user to cook small batches of food rapidly and independently, with a minimum amount of labor and energy, with an economical equipment arrangement while still retaining the health benefits of direct steam cooking.